Waveguide shape control and loss properties of light-induced self-written (LISW) optical waveguides

We show the feasibility of automatic waveguide formation by means of the self-trapping effect of multimode optical fiber irradiation into a photopolymerizing resin. By using a graded-index multimode optical fiber, we experimentally obtained a straight waveguide of over 20 mm in length. It is shown that its growth properties, such as waveguide shape and diameter, depend on the propagation modal distribution along the optical fiber used for the waveguide formation. Moreover, an all-solid polymer optical waveguide that relies on the selective photopolymerization proceeding into the photopolymerizing resin mixture is also demonstrated. We call this type of waveguide a light-induced self-written optical waveguide. The measured propagation loss in the waveguide is 1.0 dB/cm or less for the wavelength range 0.8∼1.0 μm. The proposed technology is capable of eliminating both costly lenses and the need for an alignment system from optical waveguide devices.